2014 Poster_3_6
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This study examines manufacturing thin steel sheets through direct strip casting (DSC), which simplifies production and reduces energy consumption by 90% compared to conventional methods. DSC results in a microstructure with an average grain size of 55 μm. Atom probe tomography revealed nano-scale vanadium-rich clusters not observable through transmission electron microscopy. These clusters are responsible for retarded recrystallization and fine grains during rolling and annealing of vanadium-alloyed strip cast steels. The project investigates the influence of solute elements like carbon and vanadium on microstructural development during strip casting and secondary processing through a multi-scale approach.
2014 Poster_3_6
- 1. This study examines the possibility of manufacturing thin sheets of steel in an environmental friendly manner and properties that are superior to conventionally manufactured ones. APT revealed the presence of nano-scale Vanadium rich clusters that were not observable using TEM. Concurrent precipitation of these clusters in vanadium alloyed strip cast steels are responsible for the retarded recrystallization and fine grains. 20 nm Deakin University CRICOS Provider Code: 00113B INTRODUCTION Out of 1.4 billion tonnes of steel manufactured every year, almost 50% are thin flat products. Conventional manufacturing methods demand nearly 1.8x109 Joules of energy to produce one ton of thin strip steel. Alternatively, to eliminate the energy intensive processes, a new and emerging technology is manufacturing steel sheets directly from molten metal by Direct strip casting (DSC). DSC process not only simplifies the production route but also reduces the energy consumption by 90%, thereby reducing the harmful impact on environment. However, rapid conversion of liquid steel into thin steel strips generally results in microstructures and mechanical properties that are different to conventionally manufactured ones. Despite the significant benefits, current limited knowledge about the microstructural development during strip casting and secondary processing is hindering the advancement of DSC process. This project aims to investigate the influence of solute elements, mainly carbon and vanadium, in the microstructural development during strip casting and rolling-annealing process. A multi-scale approach, from microscopic to atomic scale, is utilized to elucidate the solute behaviour in strip cast steels. C-0.09,N-0.01 wt% and V-0.04 wt% EBSD analysis showed that DSC produces a highly complex microstructure with an average grain size of 55 µm. 0 0.2 0.4 0.6 0.8 1 1.E+1 1.E+3 1.E+5 FractionRecrsytallized Time (s) Recrystallization studies showed a significant difference in kinetics as well as the grain size evolution due to Vanadium addition. 0 10 20 30 40 50 60 70 Grainsize(µm) 0wt% V 0.04wt% V 0.04 wt% V Strip-Cast Recrystallized 0 2 4 6 8 10 12 14 16 -1 0 1 2 3 Concentration(at%) Distance (nm) C % N % P % S % Cu % V % ATOM PROBE TOMOGRAPHY Effect of clusters in Direct Strip Cast steels MAHENDRA RAMAJAYAM, A.Prof. NICOLE STANFORD & Prof. PETER HODGSON Institute of Frontier Materials, Geelong Technology Precinct. SIGNIFICANCE RECRYSTALLIZATION 50% Cold Rolling + 650°C annealing DSC MICROSTRUCTURE Matrix Cluster